How to charge EN EL-15 external charger for Nikon D7000 digital camera?

I'm having a hell of a time trying to figure this out. I'm loaning a camera from my college for the photography class I'm in the camera is a Nikon D7000 with 55-200 mm lens. Since I'm loaning it, it didn't come with a freaking manual. It also came with an external battery thing that locks onto the bottom of the camera. It's supposed to be able to come out & you plug it into the wall to charge the battery & put it back in. But the problem is it's supposed to only take 2 hours to charge & the light becomes solid. I plugged it in before I went to bed last night & it was still blinking this morning. I slept for longer than 2 hours. Is something wrong with it? Please help! If a picture is needed so you can see what mine looks like I will supply one. I just need help with this.

The D7000 uses a MH-25 or MH-25a charger. Use that.

Edit: If you have some sort of aftermarket device, does this thing have a battery in it or is it just a charger that screws to the bottom of the camera so it won't get lost? If it's only a charger, you probably need to remove the battery from the camera and insert it in to the thingy. A manufacturer and model number of this device would be helpful which allows you to go online and look for the manual. Best bet is go back to the class and ask the instructor how to use the charger.

You can download manuals for the D7000 or the battery grip online. Just do a search for D7000 Owner's manual and you will find a lot of places that have it for free, or just go to nikon's website.

If the light is still showing that the battery isn't fully charged after it's been charging over night, then it's highly likely that the battery is no longer taking a charge. It's is enormously rare that the problem is due to a problem with the charger or charging system. Batteries like the EL-15 are expected to last about 3-5 years; your battery may have a date on it showing when it was manufactured.

If after reading and following the instructions in the manual you still can't charge up the battery, take it to your school and ask for a replacement.

Nikon battery grips do not charge the batteries inside the grip. You must remove the batteries and place them in the proper charger, then return them to the grip (or camera) for use.

If the grip is off-brand, it may charge the batteries inside (still never heard of such, but you never know) but you'd need to give us make and model to be sure.

With dSLRs, you take out the battery from the camera then insert to the charger which then plugs into the wall socket. If your camera has a battery-grip, it's the same. Take the batteries out first. If you have two batteries in there and only one charger then it will be a long wait, charging one at a time. From experience, it takes about 3-4 hours to fully charge one battery. I usually just leave them charging overnight. With Nikon chargers, the light blinks when charging then stays steady on when done.

Get on the Internet, write in your search engine "Nikon D7000 Instructions Manual," click "enter," and you'll find it. Copy it to your computer or lap top or whatever. Then, make a hard copy so you can read and keep with you at all times; do the same with the battery grip.

The battery must be removed from the camera body to charge.

IF the battery does not take the charge overnight, it MAY be the battery (in most cases) but it may also be (a remote possibly) that it is the charger (my charger stopped working within a month of my getting the my 2nd camera, I called B&H Photo where I bought it, as I have done for many years, and they asked me to send it back for a replacement with a NEW Nikon brand charger).

You're "loaning" it? Are you really going to college? Sounds more like you're borrowing it. AYRTFS?

You have an external battery grip. It could take a long time to charge. Providing it has batteries inside. Have you checked?

Maybe the battery has already been broken.